# ---
# title: 193. Valid Phone Numbers
# id: problem193
# author: Tian Jun
# date: 2020-10-31
# difficulty: Easy
# categories: 
# link: <https://leetcode.com/problems/valid-phone-numbers/description/>
# hidden: true
# ---
# 
# Given a text file `file.txt` that contains list of phone numbers (one per
# line), write a one liner bash script to print all valid phone numbers.
# 
# You may assume that a valid phone number must appear in one of the following
# two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit)
# 
# You may also assume each line in the text file must not contain leading or
# trailing white spaces.
# 
# **Example:**
# 
# Assume that `file.txt` has the following content:
# 
#     
#     
#     987-123-4567
#     123 456 7890
#     (123) 456-7890
#     
# 
# Your script should output the following valid phone numbers:
# 
#     
#     
#     987-123-4567
#     (123) 456-7890
#     
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
